Synthesis, characterization and toxicological evaluation of iron oxide nanoparticles in human lung alveolar epithelial cells

The present investigation was aimed to characterize the synthesized iron oxide nanoparticles (Fe3O4-NPs) and to assess their cytotoxicity and oxidative stress in human lung alveolar epithelial cells (A-549). Fe3O4-NPs were characterized by X-ray diffraction, transmission electron microscopy, dynamic light scattering, and atomic force microscopy. The morphology of the Fe3O4-NPs was found to be variable with a size range of 36 nm. A-549 cells were exposed to Fe3O4-NPs (10–50 μg/ml concentrations) for 24 h. Post exposure, cytotoxicity assays (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide, MTT; neutral red uptake, NRU; and cellular morphology) and oxidative stress (lipid peroxidation, LPO and glutathione, GSH) were evaluated. Further, intracellular reactive oxygen species (ROS) generation and mitochondrial membrane potential (MMP) were also studied. MTT and NRU assays revealed a concentration-dependent decrease in the cell viability of A-549 cells. Fe3O4-NPs exposed cells also altered the normal morphology of the cells. Furthermore, the cells showed significant induction of oxidative stress. This was confirmed by the increase in LPO and ROS generation, and the decrease in the GSH level and MMP. Our results demonstrated that Fe3O4-NPs induced cytotoxicity is likely to be mediated through the oxidative stress and ROS generation in A-549 cells.